Mitsubishi Heavy Industries SRK20ZG-S Tech Manual page 24

(5) Heating overload protective control
(a) Operating conditions: When the unit is operating with the outdoor unit speed other than 0 rps or when the outdoor air
(b) Detail of operation:
1 Taking the upper limit of control speed range at 60 rps, if the output speed obtained with the fuzzy calculation exceeds the
upper limit, the upper limit value is maintained.
2 The lower limit of control speed is set to 40(35) rps and even if the calculated result becomes lower than that after fuzzy
calculation, the speed is kept to 40(35) rps. However, when the thermo becomes OFF, the speed is reduced to 0 prs.
3 Inching prevention control is activated and inching prevention control is carried out with the minimum speed set at 40
(35) rps.
4 The outdoor fan is set on 2nd speed.
(c) Reset conditions: When the outdoor air temperature drops below 21ºC.
Note (1) Values in ( ) are for Type 50.
(6) Heating low outdoor temperature protective control
◆ <I>
(a) Operating conditions: When the outdoor air temperature sensor (Th5) is 4ºC or lower continues for 5 minutes while the
(b) Detail of operation:
1 When the command speed is less than 40(22) rps, the command speed is forcibly set at 40(22) rps. However, when the
thermo becomes OFF, the speed is reduced 0 rps.
2 Inching prevention control is activated and inching prevention control is carried out with the minimum speed set at 40
(22) rps.
(c) Reset conditions:
1 When the outdoor air temperature sensor (Th5) becomes 6ºC or higher.
2 When the inverter command speed is 0 rps.
◆ <II>
(a) Operating conditions: When the outdoor air temperature sensor (Th5) is 0ºC or lower continuously for 30 seconds while
(b) Detail of operation:
(c) Reset conditions:
1 When the outdoor air temperature sensor (Th5) becomes 2ºC or higher.
2 When the inverter command speed is 0 rps.
◆ <III> (SRK50ZG-S only)
(a) Operating conditions: When the outdoor heat exchanger sensor (Th4) is –10ºC or lower continuously for 10 minutes
(b) Detail of operation:
(c) Reset conditions:
1 When the outdoor heat exchanger sensor (Th4) becomes -7ºC or higher.
2 When the inverter command speed is 0 rps.
3 After 2 minutes have passed since this control started.
temperature sensor (Th5) rose beyond 22ºC for 30 seconds continuously.
outdoor speed is other than 0 rps.
When the either of the following condition is satisfied.
the outdoor speed is other than 0 rps.
The outdoor fan motor speed is stepped up by 1(2) speed step. (Upper limit 7th speed)
When the either of the following condition is satisfied.
while the outdoor speed is other than 0 rps.
When the command speed upper limit is set at 50 rps.
When the either of the following condition is satisfied.
-
21
-